In the past it has been common to supply a wooden knee platform assembly kit along with an artificial limb for above-the-knee amputees. Because the alignment and overall length of the artificial limb are crucial to proper operation, and because each stump socket must be custom made for each individual amputee, the prior art provided this wooden knee platform assembly kit to attach the knee platform to the lower end of the stump socket. Such attachment must be aligned and sized properly for each individual patient. Several such wooden knee platform assemblies are shown in a brochure of United States Manufacturing Company entitled "Endoskeletal Prosthetic Systems" at pages 52-59 attached to the Prior Art Statement filed along with the present application.
The procedure used in the prior art to align and attach the artificial limb knee bracket casting, used for attaching the lower leg portion of the limb containing the mechanical cadence apparatus to the stump socket, is shown, e.g., in a manual of United States Manufacturing Company entitled "Hydra-Cadence Guide Book". A copy of that book is also attached to the Prior Art Statement referred to above.
The pertinent portion of such procedure involves first properly aligning the lower leg cadence portion of the artificial limb to the stump socket on the patient's leg with the patient standing. The above referenced manual shows a wooden stump socket; however, it is now also common to form the socket of a lamination of suitable material, e.g., organic plastic material or hardenable organic polymer foam materials. Steps 11 and 13 at page 18 of the above referenced manual show the artificial limb, with a lower leg cadance portion simulator, in an alignment jig, with an alignment coupling in place. The alignment coupling is a pair of plates, one tripod mounted upon the other. Mechanical means are provided to adjust the distance between the plates and the angles of the plates to custom-fit the lower leg portion of the artificial limb to the stump socket. In the case of the wooden stump sockets shown in the above referenced manual, the lower end thereof is cut flat to receive one plate of the alignment coupling. In the case of currently used laminated or otherwise formed stump sockets, a lower end block is provided to receive the one plate of the alignment coupling. The upper and lower portions of the artificial limb are removed from the jig after certain measurements are recorded with the whole unit in the jig. The above referenced manual shows a horizontal alignment jig; however it is also now common to use a vertical alignment jig, e.g., a Hosmer "Milmo", verticle duplication machine.
The knee bracket casting is then placed on the knee platform. The knee platform is a flat generally rectangular piece of wood having a pair of bolts extending through it from a reinforcing plate and protruding from the lower side thereof. Also attached to the lower side is a socket plate containing receiving sockets for a pair of posterior hex spacers with studs, which screw into a respective one of the receiving sockets. Integral with the socket plate is a metal reinforcing strap.
The knee bracket casting, with the attached cadence mechanical apparatus for the lower leg portion of the artificial limb, is attached to the knee platform by a pair of anterior hex spacers which screw onto the bolts and by the pair of posterior hex spacers with studs which screw into the sockets.
The knee platform and attached cadence mechanism is then placed in an alignment jig, which has been previously set into proper alignment of the lower leg portion of the artificial limb and a stump socket for a particular patient, along with the proper length and foot alignment for that patient as described above with respect to the use of the alignment coupling. The lower leg mechanical portion has also been properly aligned to the knee bracket casting. Once on the jig, the knee platform is then leveled, if necessary, to a 90.degree. angle to the jig horizontal.
The stump socket is then brought into contact with the upper side of the knee platform and the stump socket is trimmed in length as necessary. Thereafter, the outline of the lower end of the stump socket is traced on the knee platform.
The knee platform and stump socket are then removed from the jig and holes drilled through the knee platform for reinforcing screws to attach the knee platform to the stump socket. The knee platform is then glued to the stump socket and the reinforcing screws installed. This procedure of using reinforcing screws is only applicable when the stump socket is made of wood. Currently it is common to use certain suitable rigid urethane foams for the stump socket, in which event no reinforcing screws are used. Certain other steps are then carried out to align the foot portion of the lower leg portion of the artificial limb, which are not pertinent to the present invention.
A spare temporary knee bracket casting is then attached to the bolts and sockets on the lower side of the knee platform and a wooden fairing is put in place onto the lower side of the knee platform. The wooden fairing has a cut-out conforming generally to the outline of the spare knee bracket casting. The wooden fairing is temporarily held in place frictionally, by attaching the plastic knee cap to the knee bracket casting. The knee platform and the fairing are then cut and sanded to conform to the shape of the lower end of the stump socket and, in the case of a wooden stump socket casting, a channel is cut for the metal reinforcing strap which is then screwed into the channel. In the case of urethane foam stump sockets the metal reinforcing strap is attached to the stump socket by embedding it in the foam.
The knee cap and fairing are then removed and grooves are cut using, e.g., a rounded file, in the posterior portion of the knee platform to allow for clearance of the side frames of the cadence mechanism when the artificial limb is flexed. The temporary knee bracket casting must be removed to fully cut and shape the grooves.
The sockets in the knee platform and the extending portions of the bolts in the knee platform are then coated with a lubricant, e.g. silicon, and a piece of stockinette is pulled over the end of the knee platform and stump socket casting making holes for the bolts. The stockinette is painted with a polyester resin over the distal end of the knee platform and for several inches along the stump socket, avoiding coating the bolts. A piece of PVA sheeting is then pulled over the distal end. The PVA sheeting is taped down to insure it conforms to the shape of the previously cut grooves.
The temporary knee bracket casting is then coated with the silicon lubricant and the knee bracket casting, wooden fairing and knee cap are placed in position and secured by the anterior hex spacers, posterior hex spacers with studs and the knee cap screws. Tape is then supplied to further hold the fairing in place and the excess stockinette is cut away, along with the removal of the tape, once the resin hardens.
The knee cap, fairing and temporary knee bracket casting are then detached and the PVA sheeting is removed. Further lubricant, e.g. silicon grease is applied to the temporary knee bracket casting and it is reinstalled on the knee platform. Modeling clay is then applied to the knee platform to provide a seal between the knee platform and the temporary knee bracket casting. The fairing is then placed on the knee platform. The seal prevents later-to-be-applied resin from entering between the knee platform and the knee bracket casting. A clay seal is then formed on the fairing around the circumference of the knee cap, which is then put in place and the excess clay trimmed.
Clay is then used to seal all of the openings in the knee cap plastic piece. Finally a stockinette is put in place over the whole assembly of the stump socket casting and knee platform and knee cap assembly. A PVA bag is pulled over the stockinette and resin poured into the bag to form the stockinette into a hardened smooth outer covering for the upper portion of the artificial limb.
The stockinette is trimmed away from the knee cap area, once the resin hardens, being careful to trim at about one half-inch overlap onto the knee cap and fairing. The knee cap and temporary knee bracket casting are removed. The edges of the fairing are then trimmed and all modeling clay removed from inside the fairing and from the knee cap.
It is thus apparent that the above described procedure is very time consuming and messy. It contains several steps which if improperly carried out could lead to an improper alignment or fit for the artificial limb, necessitating repeating the process. It also involves much skilled labor and the use of large and expensive cutting and wood finishing machinery in the prosthetic laboratory. There is, therefore, a need for a simpler method and apparatus for attaching the lower portion of the artificial limb to the stump socket while still maintaining the proper alignment and sizing.
The problems enumerated in the foregoing are not intended to be exhaustive, but rather are among many which tend to impair the effectiveness of the previously known methods and apparatus for aligning, sizing and finishing the attachment of the stump socket portion to the lower leg portion of an artificial limb for above-the-knee amputees. Other noteworthy problems may exist; however, those presented above should be sufficient to demonstrate that the prior art method and apparatus for aligning sizing and finishing the attachment of the stump socket and lower leg portion of an artificial limb for above-the-knee amputees have not been altogether satisfactory.
The present invention, therefore, relates to a modular knee finishing block. More particularly, the present invention relates to a molded rigid knee finishing block having an upper surface and a lower surface, and a curved tapered surface extending between the upper and lower surfaces and the edges of the posterior surface. A knee bracket casting receiving cavity is formed in the finishing block and has a receiving surface with a plurality of attachment members opening onto the receiving surface and each containing a passage between the receiving surface and the upper surface. A pair of posterior flexion clearance grooves extend from the receiving surface to the posterior surface. A finishing plug conforms to the shape of the cavity and grooves and has a domed surface which assists in shaping the finished outer surface of the upper leg portion of the artificial limb. An alignment duplication mandrel and alignment plate is used to hold the knee finishing block in an aligned position to duplicate the knee block's alignment in the finished artificial leg.
Examples of the more important features of the present invention have thus been summarized rather broadly in order that the detailed description which follows may be better understood, and in order that the contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described hereinafter and which will form the subject of the appended claims. These other features and advantages of the present invention will become more apparent with reference to the following detailed description of a preferred embodiment thereof in connection with the accompanying drawings wherein like reference numerals have been applied to like elements.